Alamo, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

009
FXUS66 KMTR 181956
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1256 PM PDT Wed Jun 18 2025

...New SYNOPSIS, SHORT TERM, LONG TERM, FIRE WEATHER...

.SYNOPSIS...
Issued at 1255 PM PDT Wed Jun 18 2025

Cooling trend begins on Thursday and continues through the weekend.
Gusty winds and low daytime humidities lead to elevated fire weather
conditions in the interior. Seasonal conditions resume early next
week.

&&

.SHORT TERM...
(This evening through Thursday)
Issued at 1255 PM PDT Wed Jun 18 2025

Satellite imagery shows patchy stratus lingering at the immediate
coast, with general clearing through the rest of the afternoon.
Overnight, a cold front currently analyzed over the North Coast
approaches the region, and while it will not progress further south
than the North Bay, the associated upper level low coming into the
Pacific Northwest will still provide enough wind aloft to disrupt
stratus formation, with any stratus overnight limited to the coastal
regions and perhaps parts of the East Bay west of the Berkeley-San
Leandro Hills. Speaking of winds, gusty onshore winds will develop
this afternoon with peak gusts up to 25 to 30 mph through gaps,
passes, and the Salinas Valley, but the winds won`t diminish as much
as they typically would overnight, especially along the coast and
across the higher elevations of the North and East Bay. These gusty
winds will lead to increased fire weather threat across the interior
(see FIRE WEATHER below).

Today sees the last day of warm conditions across the region with
high temperatures ranging in the lower 90s to near 100 inland, the
70s and lower 80s along the Bayshore, and the lower to middle 60s
along the Pacific coast. Low temperatures on Thursday morning range
from the lower to middle 50s in the lower elevations, into the 60s
for the higher elevations. Thursday`s highs will dip due to the
influence of the upper low, with highs reaching the lower 70s to the
lower 80s inland and the upper 50s to middle 60s along the coast and
Bayshore. Light coastal drizzle is also possible tonight into
Thursday morning.

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 1255 PM PDT Wed Jun 18 2025

Breezy and chilly conditions continue through the weekend, with high
temperatures dropping to the 70s inland and the upper 50s to lower
60s along the coast, or around 8 to 15 degrees below the seasonal
average, on Friday and Saturday. The upper level low moves
northeastward into the Canadian prairie provinces, but some of its
energy remains trapped in the western United States, courtesy of a
very strong upper level ridge centered over the Ohio River Valley
and the Northeastern US. Temperatures will begin to rise on Sunday,
and by the middle of next week, it may still feel chilly along the
coast, but temperatures in the inland valleys should be much closer
to the seasonal averages. CPC guidance suggests that temperatures
remain near or slightly below seasonal averages into the first
couple days of July, with precipitation totals remaining near the
seasonal averages (read: almost nothing) for the same period.

&&

.AVIATION...
(18Z TAFS)
Issued at 1044 AM PDT Wed Jun 18 2025

VFR anticipated at most TAF sites, except Half Moon Bay and the
Monterey Bay Terminals. Otherwise, generally medium confidence in
forecast flight category, with low to medium confidence in
surface wind forecasts. IFR will linger a little longer at KHAF,
before stratus is shunted offshore by daytime heating around 21
UTC. A cold front was analyzed across the Pacific NW this morning
per WPC guidance. Some hi-res guidance does suggest that winds
become more NW`ly at KSTS this afternoon for a few hours. There`s
a brief window for MVFR BR at KSTS during the morning hours on
Thursday, should winds abate. There`s a brief window for MVFR
stratus at KOAK during the morning hours. Otherwise, winds will
remain elevated with gusts between 20 and 25 knots.

Vicinity of SFO...VFR is forecast throughout the TAF period, with
medium confidence. There`s some guidance that suggests a brief
window from 12-15 UTC of MVFR at SFO, but confidence is too low to
include at this time. Otherwise, W`ly winds will gust to around
25 knots, largely during the afternoon hours. Sustained winds will
remain elevated through the entire TAF period with speeds near 12
knots.

SFO Bridge Approach...Similar to SFO with VFR.

Monterey Bay Terminals...An eddy continues to swirl across
Monterey Bay, but will eventually dissipate through the afternoon.
Still, intermittent IFR to borderline LIFR is forecast for a few
more hours at KMRY. Confidence in timing is medium. VFR is
anticipated through the evening hours with IFR
Monterey Bay Terminals...An eddy  cigs more probable
to return at KMRY around 05Z and linger through the TAF period.
Confidence in IFR cigs is low to medium. If onshore flow is
weaker than anticipated, VFR may continue through the pre-dawn
hours. At KSNS, VFR will dominate the TAF cycle, with a short
window of intermittent IFR during the pre-dawn hours (10-14 UTC)
on Thursday.

&&

.MARINE...
(Today through Monday)
Issued at 248 AM PDT Wed Jun 18 2025

Gale Warnings are in effect for the coastal jet areas south of
Point Reyes and Point Sur and across the outer coastal waters.
Hazardous conditions continue through the forecast period with
gusty northwesterly winds and moderate to rough seas continue.
Significant wave heights build to 10 to 12 feet across the coastal
waters Thursday into the weekend.

&&

.FIRE WEATHER...
Issued at 1255 PM PDT Wed Jun 18 2025

A period of elevated fire weather threat begins on Thursday as
strong winds gusting at 20 to 35 mph and daytime relative humidities
of 15 to 25% develop across the interior, with the biggest threat
coming in the interior mountains of the North Bay, the interior East
Bay, the eastern Santa Clara Hills, and the Gabilan Range in
interior Monterey and San Benito Counties. Fuels have been curing
across the interior, especially across the finer fuels of grass and
brush, and there`s already been several notable grass fires across
the interior portions of the region. However, the fact that winds
will remain onshore and temperatures will cool will keep fire
weather conditions below critical levels. The fire weather threat
continues into the weekend, before gusty winds begin to subside
heading into the early part of next week.

DialH

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay-SF
     Bay N of Bay Bridge.

     Gale Warning until 9 AM PDT Thursday for Pt Arena to Pt Reyes 0-
     10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras
     Blancas 0-10 nm.

     Small Craft Advisory until 9 AM PDT Thursday for Pigeon Pt to Pt
     Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory until 3 PM PDT this afternoon for Pigeon Pt
     to Pt Pinos 10-60 NM.

     Gale Warning until 9 AM PDT Thursday for Pigeon Pt to Pt Pinos
     10-60 NM.

&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...Bain
MARINE...MM

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